1. Field of the Invention
The invention relates to selvage insertion apparatus for a weaving machine, with at least one insertion arm and at least one thread clamp which have a drive device to control a weft thread and which operate from a common drive shaft.
2. Description of the Related Art
With regard to known selvage insertion apparatus of the above-mentioned type U.S. Pat. Nos. 4,905,740; 4,909,283 and 4,957,145; European patent A 0,626,476), the power for the drive shaft is taken from a weaving machine's main shaft. Accordingly the selvage insertion apparatus operates synchronously with the weaving machine's main shaft and runs according to this main shaft's speed.
Furthermore U.S. Pat. No. 5,158,119 discloses selvage insertion apparatus including an insertion arm, a thread clamp and a thread cutter each with its own drive motor. The insertion arm is axially displaceable by one motor and rotatable by another motor. The thread clamp and the thread scissors each are axially displaceable by their own motors. This selvage insertion apparatus is operated by a microprocessor that controls the individual motors. This microprocessor also receives data concerning the weaving machine's weaving cycle. Position sensors are combined with the insertion arm and immediately detect operational malfunction, whereupon the microprocessor shuts down the motors to prevent collision between the insertion arm and/or the thread clamp and the scissors and the reed.